1. Field of the Invention
The invention relates to dot-matrix printers, and more particularly to a line head printer having dot-matrix pins or heating elements fixed across the width of a print sheet.
2. Description of the Related Art
There are two types of dot-matrix printers: a line head printer having a fixed print head and a moving head printer having a print head which shuttles across the print sheet and is provided with a plurality of dot-matrix pins or heating elements arranged in an order perpendicular to the width of a print sheet.
The line head printer is provided with no head moving mechanism and has a simple mechanical structure. However, the moving head printer requires a head moving mechanism and has difficulty increasing its print speed due to mechanical limitations. Thus, the line head printer is faster.
A line head printer has a plurality of rows, each consisting of dot elements, and moves a print sheet past the plurality of rows every time the dot elements in the plurality of rows have been energized. For example, suppose that a line head printer contains n rows equivalent to one print line where each row consists of a plurality of dot elements. Print data is input for every row until n rows of data (i.e. one print line) can be printed. Therefore, the line is printed without moving the print sheet. The line head printer then scrolls the print sheet forward a distance equivalent to one print line (i.e. n rows) after the n rows of data have been printed and repeats the process until all data has been printed.
The process of printing data with a moving head printer is somewhat different. The end of the moving head has a plurality of dots, m, which is equivalent to a segment of a print line. Print data equivalent to the m dots is input to an end of the moving head and the dots in the moving head are energized thus printing this segment of the print line. The moving head then moves forward horizontally across the print sheet a distance equivalent to the segment of the print line. Data equivalent to the m dots is again input to the moving head and the above process is repeated until an end of the line is reached. Then, the printer scrolls the print sheet forward to the next line and the entire process is repeated until all data has been printed.
Many printers use a combination of both the line head and moving head printer technologies. Although interchangeability between the function of a line head printer and that of a moving head printer is desireable, to date, no such interchangeability has been available. Therefore, print data for a line head printer cannot be used by the moving head printer and vice-versa